In general, you will get 5-10 potatoes per plant with 3-5 a medium to big size and the rest smaller potatoes. A different way to look at it is total yield and not potatoes per plant. In a decent year you can expect 10x the amount of seed potato planted. So if you plant 10 lbs. of seed potato you should expect to harvest 100 lbs. of potatoes.
Potato variety plays a part in both the amount of potatoes you get per plant and total weight yield. Some fingerling potato varieties you can harvest 30 potatoes off of one plant.
How many eyes or sprouts you leave on your seed potatoes and how far apart you plant your potatoes will affect the number you get per plant but probably not your total yield. With a higher number of eyes or sprouts on your seed potato you will get a higher number of potatoes per plant but they will be a smaller size.
Same thing with the spacing of your plants. If you choose to plant your potatoes 8″ apart as opposed to 12″ apart you will end up with more potatoes overall but they will be smaller than they would have been spaced further apart.
There are factors that will influence the overall yield of potatoes. Nutrients in the soil, plant location sun vs shade, the weather, and pest and disease problems all play a role. If you have a very hot or wet summer you can come up with a lower yield or could end up with disease and losing a significant part or your whole crop. A bad beetle problem can do the same.
Potato Care Tips to Increase Yields
Chitting Properly – Chitting, or pre-sprouting, your potatoes before planting can give them a two week head start to the season. This gives you two weeks longer of a growing season and can really get them rocking as soon as they hit the dirt. This is especially important because in the early spring conditions are just right for potato growth, before the heat of the summer comes a knocking. It can also prevent rotting from seed potatoes sitting inactive in the cold and wet early spring soil. Check this article out to learn proper chitting.
Weeding & Pests – Keeping your potato patch weed free will help to prevent disease and to make sure your potatoes are not sharing the nutrients in the soil with plants you don’t want.
If you see pests get on them fast and hard to eradicate them and minimize the damage they do. The above mentioned Colorado Potato Beetle is the most likely culprit.
Also rotate your potato crop every year so you don’t give pests or disease a chance to accumulate. Some gardeners take this as far as getting new potato seed every year and pulling out volunteer potato plants from the year before.
Spacing of The Plants – It’s important to give your potato plants enough space. Planting too many seed potatoes in an area can lead to poor yields. More soil area for the tubers and roots and more foliage area for the plant will lead to bigger yields. Here’s an article on proper potato spacing.
Plant Location (Sun vs Shade) – Potatoes planted in full sun will give a higher yield than those in a lot of shade. A general rule of thumb is you want at least 6 hours of full sunlight a day. Some adjustments can be made for the variety of potato and time of planting.
If you’re planting an early variety potato early in the spring you want to give it as much full sun as possible. If you’re planting a potato patch later in the season you would want to consider giving it a fair amount of shade so that it could get it’s vegetative growth in without being fried.
Best Soil & Fertilizer for Potatoes
You want to make sure your soil is up to snuff by fertilizing the soil. Farmers do soil tests and then get a customized fertilizer based on the results. This is the best way to ensure the potato plant has all the nutrients it needs. Here’s a home test kit that will give you your soil PH and 13 nutrient levels.
Over fertilization can lead to strong and excessive green foliage growth and diminished growth of the tubers under ground. This is especially true of too much nitrogen around flowering time when the potatoes are in the bulking phase If the soil is under fertilized you will see the plants turning yellow well before they should be and new growth of leaves coming out yellow.
The three numbers in fertilizers stand for N-P-K, nitrogen – phosphorous – potassium. These are the major nutrients the plant needs followed by calcium, sulfur, magnesium, and more.
When fertilizing you can choose between a standard fertilizer or an organic mix and many different schedules for fertilizing. Jack’s Classic is a good standard water soluble fertilizer that measures 20-20-20. You can also measure out half the ingredients and use as a 10-10-10. A combination of side-dressing and broadcasting is recommended for application of standard fertilizer at planting time.
Organic Plant Magic is an organic all-purpose water soluble fertilizer with a N-P-K of 6-5-5 plus 9% calcium, 2.6% sulfur, and 1.2% magnesium. It also has other micro-nutrients and beneficial soil bacteria.
As the season goes on potatoes need less nitrogen and more phosphorous and potassium. Nitrogen helps with foliage growth above ground and phosphorous and potassium with the growth of the plants roots and fruits, in potatoes case tubers under the ground.You can figure that this switch happens sometime around 6 weeks after the plant emerges. Garden Tone is an organic 3-4-4 fertilizer and here’s a standard fertilizer that measures 10-25-16.
How Often to Water Potatoes
Watering can be tricky as you don’t want to over or under water. Here are a few guidelines to go by. In general you want to water 1/2″ of water twice a week until the potatoes start to flower, then once they flower you’ll want to water 1/2″ of water about four times a week, and then less as the potatoes start to turn yellow and die off. Stop watering completely two weeks before harvesting so the potatoes can cure and the skin toughen up before being taken out of the ground.
Potatoes need 1-2 inches of water a week whether that comes from the hose or the sky. Aim for 1″ during the early and late season and 2″ once flowering and/or consistent hot weather comes. Watering heavily as opposed to more often is favored because it gets the water deeper and will provide water to the plant for longer and encourage deep healthy root growth. You can water before light rains or after to make for a deeper watering.
To keep your watering accurate invest in a rain gauge. This way you can see how much rain has actually fallen and if you use a sprinkler measure how much water it puts off in a certain amount of time.